code: def _fill_buf(self):
      data = self._make_range_request()
      if data is None:
          return None
      if data:
          buf = BytesIO(data)
          self._pos += len(data)
          self._tail = b""
          return buf
      else:
          return None
  
file_path: metaflow/metaflow/plugins/azure/azure_tail.py
imports: from io import BytesIO
  from azure.core.exceptions import ResourceNotFoundError, HttpResponseError
  from metaflow.exception import MetaflowException
  from metaflow.plugins.azure.blob_service_client_factory import get_azure_blob_service_client
  from metaflow.plugins.azure.azure_utils import parse_azure_full_path
label_desc: Use image node_id 4 for calling the AzureTail obj's underlying member method code with example usage: obj._fill_buf() and returns: None, buf, None